Yet another problem. Tractor started. Was warming it up. I tested the lights. Most were working then suddenly the headlights flickered and died. All lights and instruments lost power except the ampmeter. Turned off the tractor and as expected cant start it. No lights, instruments or crank. Does this sound like the ignition switch issue that i have noticed on other threads? I had noticed last week that i had lost all instruments for only a few seconds.
Jinma 254 ignition switch problem
- Thread starter Jimmy254
- Start date
piper184
Gold Member
Possibly. There should be a run position to the left of off, does that work?
The contacts inside the key switch are notorious for wearing out and if the contact for power in is shot, then nothing else will work.
You can see how to wire a replacement here:
My key switch is OEM and never given me any trouble (now I'll be jinxed) but I installed a solenoid for the glow plugs many years ago. From the factory all the amperage for the glow plugs ran through the switch and was the cause for failure in a lot of them. Also the wires were woefully undersized for 30A.
The contacts inside the key switch are notorious for wearing out and if the contact for power in is shot, then nothing else will work.
You can see how to wire a replacement here:
My key switch is OEM and never given me any trouble (now I'll be jinxed) but I installed a solenoid for the glow plugs many years ago. From the factory all the amperage for the glow plugs ran through the switch and was the cause for failure in a lot of them. Also the wires were woefully undersized for 30A.
piper184
Gold Member
Use a multi-meter or a test light and start following the power from the battery to the starter to the amp meter to the switch.
And as always, check the grounds, check the grounds, check the grounds (advice from an old farmer....)
Low quality parts, age and weather do take a toll.
And as always, check the grounds, check the grounds, check the grounds (advice from an old farmer....)
Low quality parts, age and weather do take a toll.
Ive recently put in a new battery and cleaned and tightened connections. As i was checking continuity which i had discovered was broken between the white starter wire and the ammeter input to the ignition switch i somehow restored continuity but i dont know how. I reconnected battery earth and tried starting. All instrument lights came on however the glow plugs are not drawing current when key start is on heat mode. Glowplugs were all working fine this morning. Ill have to study the schematic diagram to work this out.
I'm stumped. Im now consistently getting 12v to cable no 5 spade terminal at back of starter switch which comes from the amp meter. That is the only voltage test ive done. Continuity results seem to change. With key in off position i see an open circuit with between cable 5 and the other posts which is expected however occasionally i see a reading of 1112 on the meter. What does this mean. Could it be a short within the starter switch? At one stage the amp meter showed to he glow plugs drawing current again but when i went to the start position i could hear this ever so slight static nouse (like a tiny arc sound) within the switch and then all lights out and no crank again. Is this enough evidence to focus on replacing the key starter switch? Does it definetly rule out the clutch switch? The lights on the dash drop out independently of the clutch being engaged so that is why i doubt the clutch switch
piper184
Gold Member
Ok, let's go through the wiring.
Battery to starter, large cable - good
Starter to fuse in block # 2 should be at least a 10 ga. wire. OEM is woefully undersized for 30 amps. This wire is always suspect because it has poor quality terminals crimped on it and they are known to get loose or break. They also have a tendency to pop out of the back of the block when you insert the fuse and don't make good contact.
Fuse to amp meter #3. exact same thing as #2.
All current for the tractor except for the starter motor itself goes through these two wires. It would be easy enough to make up a temporary jumper wire with an inline fuse to go from the starter to the back of the key switch, bypassing #2, #3, #5 and the amp meter. For the purposes of testing, you can skip wire #4, just realize that the alternator won't work and you may see the light on the dash come on when in the run position.
At this point you have known good power to the key switch and you can test each position from there. Everything should work with the exception of the alternator. If not, you have a bad switch. Since you could hear arcing sounds, it is very possible the switch is bad.
If the jumper wire solves your problem, I would replace 2, 3, and 5 with good wire and terminals.
A note about the amp meter. Most of them have a shunt internally so that if the meter itself fails it will still pass current through the terminals but the needle won't move. I don't know if these OEM units have that fail safe feature or not.
The clutch switch is inserted in the circuit that goes to the starter relay. It would have no effect on any of the rest of the wiring. If you suspect it, just pull the wires off and connect them together. If that switch fails you get dead silence when the key is turned to start. No click, no nothing.
The biggest deficiency of the whole system (other than wire size and terminal quality) is running all the current for the glow plugs through the key switch. 30 amps is a lot to pass through those little contacts and they arc a little each time they are used. Eventually they wear out. If you loose the contact at terminal 3 then only the glow plugs quit, but if the contact at terminal 1 gets burned, it is game over for all the electrical because everything is downstream of terminal 1.
I hope this helps some and don't be afraid to ask more questions if I confused you.
Once you get this issue sorted out, if you would like we can go over how to install a relay for the glow plugs to save the switch. It is fairly easy and not very expensive.
Battery to starter, large cable - good
Starter to fuse in block # 2 should be at least a 10 ga. wire. OEM is woefully undersized for 30 amps. This wire is always suspect because it has poor quality terminals crimped on it and they are known to get loose or break. They also have a tendency to pop out of the back of the block when you insert the fuse and don't make good contact.
Fuse to amp meter #3. exact same thing as #2.
All current for the tractor except for the starter motor itself goes through these two wires. It would be easy enough to make up a temporary jumper wire with an inline fuse to go from the starter to the back of the key switch, bypassing #2, #3, #5 and the amp meter. For the purposes of testing, you can skip wire #4, just realize that the alternator won't work and you may see the light on the dash come on when in the run position.
At this point you have known good power to the key switch and you can test each position from there. Everything should work with the exception of the alternator. If not, you have a bad switch. Since you could hear arcing sounds, it is very possible the switch is bad.
If the jumper wire solves your problem, I would replace 2, 3, and 5 with good wire and terminals.
A note about the amp meter. Most of them have a shunt internally so that if the meter itself fails it will still pass current through the terminals but the needle won't move. I don't know if these OEM units have that fail safe feature or not.
The clutch switch is inserted in the circuit that goes to the starter relay. It would have no effect on any of the rest of the wiring. If you suspect it, just pull the wires off and connect them together. If that switch fails you get dead silence when the key is turned to start. No click, no nothing.
The biggest deficiency of the whole system (other than wire size and terminal quality) is running all the current for the glow plugs through the key switch. 30 amps is a lot to pass through those little contacts and they arc a little each time they are used. Eventually they wear out. If you loose the contact at terminal 3 then only the glow plugs quit, but if the contact at terminal 1 gets burned, it is game over for all the electrical because everything is downstream of terminal 1.
I hope this helps some and don't be afraid to ask more questions if I confused you.
Once you get this issue sorted out, if you would like we can go over how to install a relay for the glow plugs to save the switch. It is fairly easy and not very expensive.
piper184
Gold Member
Bob's pin-out in the other thread is correct for the OEM switch. I hadn't seen that before. Here is my switch with different labels.
My memory had failed, there are not two run positions, there are two start positions. I have never used the one to the left (counter clockwise).
Does yours make any sounds when you try turning the key to the left? The clutch pedal would have to be depressed or the safety switch by-passed.
It is interesting that they voltage regulator is powered in the start position. I see no need for this and it may be a contributing factor in the short lifespan of the regulators.
My memory had failed, there are not two run positions, there are two start positions. I have never used the one to the left (counter clockwise).
Does yours make any sounds when you try turning the key to the left? The clutch pedal would have to be depressed or the safety switch by-passed.
It is interesting that they voltage regulator is powered in the start position. I see no need for this and it may be a contributing factor in the short lifespan of the regulators.
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Everything seems to either work or not work. That is the best way i can describe it. Except for when the glow plugs were the only things not working. Even that was not permanent because i did see them drawing power afterwards when things suddenly came alive briefly. Ill do your jumper cable test. Thks also to bob for the pin out pic. And i am very interested in installing a relay for the glow plugs once this is sorted out.
So i jumpered between the starter positive and the power in on the keystart. The switch seemed to work immediatly. I couldnt see if the glow plugs were working because the amp meter was bypassed but i could see voltage at the glow plug post of the keystarter and i could also see the lights on the dash fade a little so i tried starting and away she went. I then used the multimeter ohm meter and found a suspicious reading through the fuse box. I removed the 30amp starter fuse which looked intact. The ohmmeter would flicker between high and low readings. Anyway i replaced the fuse and so far so good. Time will tell. I removed the instrument panel to clean out behind it as it was very dusty and dirty. One of the amp meter posts had a fair bit of oxidisation on it so i cleaned the connectors up as it could be a point of failure. Here is a tip. If you have trouble screwing the main negative cable lug bolt to the chassis through the air cleaner bracket mount, loosen the opposite air cleaner bracket bolt before trying to screw in the earth terminal. Very hard to get the thread started otherwise.